swift - 在 UIVIew 的左上角创建 UILabel 并直接向下设置动画？

Question

我已经为这个新游戏工作了几个月，遇到了一个我无法解决的问题!

所以基本上我在我的 UIViewController 的右上角创建了一个“状态部分” .在这个“状态部分”会出现UILabels将状态更新保存为 Strings .这些UILabels将出现在 UIView 的最左上角并且会慢慢向下并丢失Alpha同时..一旦到达底部，最终就会消失。

我做了什么？

因此，正如您在之前的代码中看到的那样，我已经能够创建 UILabel在随机位置，但由于某种原因 UILabels在屏幕外产生。

代码

func createStatus() {


        let viewWidth = self.statusView.frame.width
        let viewHeight = self.statusView.frame.width

        let randomX = CGFloat(viewWidth / 2)
        let randomY = CGFloat(arc4random_uniform(UInt32(viewHeight)) + 50)


        let frame = self.statusView.frame.origin

        let status = UILabel(frame: CGRect(origin: CGPoint(x: CGFloat(viewWidth / 4) - 20, y: CGFloat(viewHeight - viewHeight) + 10), size: CGSize(width: 200.0, height: 50.0)))

        status.text = "This is a status"
        status.textColor = UIColor.redColor()
        status.alpha = 1
        self.statusView.addSubview(status)
        print("Status made")
        UIView.animateWithDuration(2) {
            status.center = frame
            status.alpha = 0

        }

    }

我添加了问题的图像和 UIView状态 View 也是如此。我在左上角制作 UILabel 时遇到问题，我尝试了下面的这段代码，它甚至没有在屏幕上“生成”UILabel。

let frame = self.statusView.frame.origin
CGPoint topLeft = CGPointMake(CGRectGetMinX(frame), CGRectGetMinY(frame));

Answer 1

func createStatus() {


    let viewWidth = self.statusView.frame.width
    let viewHeight = self.statusView.frame.width

    //Why are these here?
    let randomX = CGFloat(viewWidth / 2)
    let randomY = CGFloat(arc4random_uniform(UInt32(viewHeight)) + 50)


    let origin = CGPointZero//Origins are relative to superview, so top left would be (0, 0)

    //Renamed status to statusLabel so that we know its a label and not a model object
    let statusLabel = UILabel(frame: CGRect(origin: origin, size: CGSize(width: 200.0, height: 50.0)))

    statusLabel.text = "This is a status"
    statusLabel.textColor = UIColor.redColor()
    statusLabel.alpha = 1
    self.statusView.addSubview(statusLabel)
    print("Status made")
    UIView.animateWithDuration(2) {
        //Animate the origin instead of center position. 
        //The origin will be the height of the statusView - the height of your label. x stays 0 to keep it along left edge.
        statusLabel.frame.origin = CGPoint(x: 0, y: self.statusView.frame.height - statusLabel.frame.height )
        statusLabel.alpha = 0

    }, { (completed) in
        if completed {
           //If statusLabel doesn't have a superView it will be dealloc after the function goes out of scope. So remove it from superview after animaion is complete and ARC takes care of it.
           statusLabel.removeFromSuperview()
        }

    }

}